With changes in our lifestyle and aging of the population, arthritis is expected to increase in the future.
N-Acetylhydroxyproline is known as a chemical substance that shows anti-inflammatory activity (U.S. Pat. Nos. 3,891,765 and 3,932,638; Japanese Published Examined Patent Application No. 43947/72).
It is known that administration of N-acetylhydroxyproline to an animal model for arthritis after induction of arthritis can prevent aggravation of arthritis [J. Drug. Dev., 3, 135–142 (1990)]. It is also known that although N-acetylhydroxyproline shows a therapeutic effect on systemic injury of ear and tail, it shows no effect on chondral injury at joints [Pharmacological Research, 33, 367–373 (1996)].
However, it has not been known so far that N-acylated hydroxyproline derivatives such as N-acetylhydroxyproline show a preventive effect on arthritis.
Furthermore, although chondroitin, glucosamine, etc. that are the components of cartilages are known to have a therapeutic effect on arthritis (WO94/22453), there has not been known a composition obtained by the addition of an N-acylated hydroxyproline derivative thereto.